Magnetic Memory Merging Tunnel Junctions to Reduce Cost

Solution Overview

Problem

The existing methods for manufacturing magnetic memories with multivalued information recording capabilities increase manufacturing costs due to the need for separate laminated structures for tunnel junction elements, leading to higher process complexity and power consumption.

Innovation Solution

A magnetic memory design featuring first and second tunnel junction elements with a laminated structure, including a reference layer with a fixed magnetization direction, a recording layer with reversible magnetization, and an insulating layer, connected to a selection transistor and wires, allowing for selective recording and reading by controlling potential differences between the wires, thereby reducing the need for separate laminated structures and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate laminated structures are used for different tunnel junction elements to enable selective recording, then multivalued information recording capability is improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvemultivalued information recording capabilityVSAvoidmanufacturing process complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the laminated structures of multiple tunnel junction elements, making them common to all elements in the memory cell. Instead of having separate reference layers, insulating layers, and recording layers for each tunnel junction element, these layers are shared across multiple elements, thereby reducing manufacturing process complexity while maintaining multivalued information recording capability through selective magnetization reversal.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If separate laminated structures are used for different tunnel junction elements to enable selective recording, then multivalued information recording capability is improved, but manufacturing cost increases

Engineering Contradiction:

Improvemultivalued information recording capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent merges the laminated structures of multiple tunnel junction elements, making them common to all elements in the memory cell. Instead of having separate reference layers, insulating layers, and recording layers for each tunnel junction element, these layers are shared across multiple elements, thereby reducing manufacturing process complexity while maintaining multivalued information recording capability through selective magnetization reversal.

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If different laminated structures are used for tunnel junction elements to distinguish recorded information, then reading accuracy is improved, but power consumption increases

Engineering Contradiction:

Improvereading accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by giving each recording layer a distinct magnetization direction (first direction for one tunnel junction element, second direction for another) while keeping the overall laminated structure common. This localized differentiation in magnetization orientation enables accurate identification of recorded information states without requiring complex separate structures, thereby reducing power consumption for selective recording and reading operations.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design effectively suppresses the increase in manufacturing costs and power consumption while enabling multivalued information recording in a single memory cell, reducing the likelihood of recording and reading errors.

Implementation Method 1

The MRAM, which is one of the memories described above, records information by using a change in electric resistance of a memory element by reversing a magnetization direction of a magnetic body of the memory element included in the MRAM.

Methodology Applied

Scientific EffectMagnetoresistance: Magnetoresistance

Implementation Method 2

of the MRAM, greater expectations are placed on the MRAM that reverses the magnetization direction of the magnetic body by using spin torque magnetization reversal because low power consumption and high capacity can be achieved

Methodology Applied

Scientific EffectSpin torque magnetization reversal:

Data Source

PatentUS10964366B2Magnetic memory, recording method of magnetic memory, and reading method of magnetic memory

Publication Date: 2021.03.30 SONY SEMICON SOLUTIONS CORP

AI summary

There is provided a magnetic memory that can suppress the increase in manufacturing costs while recording multivalued information in one memory cell, the memory including first and second tunnel junction elements each having a laminated structure including a reference layer with a fixed magnetization direction, a recording layer with a reversible magnetization direction, and an insulating layer sandwiched between the reference layer and the recording layer, a first selection transistor electrically connected to first ends of the first and second tunnel junction elements, a first wire electrically connected to a second end of the first tunnel junction element, and a second wire electrically connected to a second end of the second tunnel junction element.